Donald Trump: Truth-teller or flip-flopper?

As he surges to the front of the GOP presidential primary, billionaire businessman Donald Trump is pitching himself as an unvarnished truth-teller - the kind of guy who will tell you what he believes, whether you like it or not. But how consistent has Trump been in his political beliefs over the years?

By some measures, it turns out, he hasn't been very consistent at all. He's running as a rock-ribbed conservative on health care, abortion, gun control, and other issues - but he hasn't always embraced the right-wing positions he's voicing on the campaign trail today.

At times, Trump has sounded more like a libertarian - or even a liberal - than voters might guess, given his current persona as a conservative warrior. And when you've sought the public eye as long and as aggressively as Trump has, it's not easy to brush your earlier statements under the rug.

Here are six issues on which Trump has flip-flopped.

Health care

Republican presidential candidate Donald Trump speaks at the Family Leadership Summit in Ames, Iowa, July 18, 2015.
Reuters/Jim Young

On health care, Trump used to be receptive to the kinds of reforms implemented by Obamacare, which have expanded insurance coverage to millions of previously uninsured Americans.

In an interview with journalist Larry King in 1999, Trump described himself as "very liberal when it comes to health care." He embraced "universal healthcare," which many conservatives see as code for another big government entitlement program.

And in his 2000 book "The America We Deserve," Trump said the U.S. should be working toward "an equivalent of the single-payer plan that is affordable, well-administered, and provides freedom of choice."

During recent stump appearances, though, Trump has channeled the overwhelming opinion of the Republican base when he's said he favors repealing Obamacare. He's called the law "the big lie," and vowed to replace it with something better and cheaper.

Abortion

Businessman Donald Trump speaks to guests gathered for the Republican Party of Iowa's Lincoln Dinner at the Iowa Events Center on May 16, 2015 in Des Moines, Iowa.
Scott Olson, Getty Images

On the question of abortion, Trump has evolved. In 1999, he described himself as "very pro-choice" on NBC's "Meet the Press."

"I hate the concept of abortion...I hate it. I hate everything it stands for," he explained. "But I just believe in choice."

In his 2000 book, he wrote, " I support a woman's right to choose but I am uncomfortable with the procedures." That language echoed many other pro-choice politicians at the time who expressed reservations about abortion itself but maintained that women should be free to choose to undergo the procedure.

Fast-forward to 2011, and Trump was singing a different tune, though he readily acknowledged his shift. As he was flirting with the idea of a Republican presidential bid in 2012, he told attendees at the Conservative Political Action Conference that he identifies as pro-life, despite embracing the pro-choice cause for decades.

"One of the reasons I changed - one of the primary reasons - a friend of mine's wife was pregnant, in this case married. She was pregnant and he didn't really want the baby," Trump said. "He was crying as he was telling me the story. He ends up having the baby and the baby is the apple of his eye. It's the greatest thing that's ever happened to him. And you know here's a baby that wasn't going to be let into life. And I heard this, and some other stories, and I am pro-life."

Drug policy

On the issue of legalizing drugs, Trump has also had a change of heart. In 1990, according to the Chicago Tribune, Trump warned that America was "losing badly" in the so-called war on drugs, and he called for a new approach.

"You have to legalize drugs to win that war," he explained. "You have to take the profit away from these drug czars."

Trump suggested the revenue accrued by legalizing and taxing drugs could be redirected into drug education and prevention efforts.

But in an interview on Fox News last month, Trump voiced a far more measured opinion on drug policy when he was asked about states like Colorado that have legalized marijuana for recreational use.

"I don't like what's coming out. I mean if you look, I'm all for medical marijuana," he said. "But what's coming out is some really bad things are happening in Colorado with respect to people...You know, a lot of people were all in favor of it and now all of a sudden they're saying it's having tremendously damaging effects to the mind, to the brain, to everything. So it's a big problem."

Gun control

U.S. Republican presidential candidate, real estate mogul and TV personality Donald Trump makes a point as he formally announces his campaign for the 2016 Republican presidential nomination during an event at Trump Tower in New York June 16, 2015.
REUTERS

On gun control, as well, Trump has steadily tacked to the right.

In his 2000 book, Trump wrote, "I generally oppose gun control, but I support the ban on assault weapons and I support a slightly longer waiting period to purchase a gun. With today's Internet technology we should be able to tell within 72 hours if a potential gun owner has a record."

Now that he's running for president as a Republican, Trump has scorned any and all restrictions on American gun ownership.

During his kickoff speech in June, Trump vowed to "fully support and back up the Second Amendment." He recalled a conversation with a woman who cited a recent jailbreak to explain her change of heart on gun control, saying she now has "a gun on every table."

Jeb Bush

Sometimes Trump has flip-flopped on his opinion of political figures as well.

In his 2000 book, he described former Florida Gov. Jeb Bush as a "good man" - a "bright, tough, and principled" person and " exactly the kind of political leader this country needs now and will very much need in the future."

Hillary Clinton

Once upon a time, Trump sounded like a big fan of Hillary Clinton as well.

In 2012, he told Fox News, "Hillary Clinton, I think, is a terrific woman. I am biased because I have known her for years. I live in New York. She lives in New York. I really like her and her husband both a lot. I think she really works hard."

And it's not just lip service: Trump has donated money to Clinton's political campaigns and to her family's charitable foundation as well. Clinton even attended Trump's wedding in 2005.

"I'm a businessman. I contribute to everybody," Trump told Fox News earlier this month. "When I needed Hillary, she was there. If I say 'go to my wedding,' they go to my wedding."

"Hillary Clinton was the worst Secretary of State in the history of the United States. There's never been a Secretary of State so bad as Hillary. The world blew up around us. We lost everything, including all relationships," he told NBC News earlier this month. "Why would she be a good president? I think she would be a terrible president."